Piston and drive assembly for use in a pump

A pump, comprising:

• a body having a central chamber with a metering chamber having an opening, a piston disposed within the metering chamber, and a moveable valve assembly for blocking the opening of the metering chamber to maintain a liquid therein;
• the piston having a first end, a second end, a member for receiving and conducting a liquid along a length of the piston and out of the first end, and means for alternately opening and closing the liquid receiving/conducting member to prevent liquid flow therethrough;
• wherein movement of the piston within the chamber of the pump along a stroke in a direction away from the valve assembly causes liquid to flow through the liquid receiving/conducting member to the metering chamber;
• and movement of the piston along a stroke in a direction toward the valve assembly causes the valve assembly to disengage from the opening and the liquid in the metering chamber to be dispelled therefrom, the force of the piston against the valve assembly causing the liquid and compressed air bubbles in the metering chamber to be dispelled out of the metering chamber.

A drive assembly for use in a pump having a body with a chamber and a piston having a longitudinal axis positioned therein, the drive assembly comprising:

• a rotatable drive shaft;
• an eccentric cam insert positioned on the drive shaft;
• a cam rod positioned on the eccentric cam insert and having a shaft with a first end;
• and
• a rocking beam having an output end, an actuator end, a mid-section, and a pivot point;
• the output end coupled to an end of the piston, and the mid-section coupled to the first end of the cam rod shaft;
• wherein when the drive shaft is rotated, the cam rod shaft is moved between a first position and a second position causing the rocking beam to pivot about the pivot point, the output end of the rocking beam to move laterally with respect to the longitudinal axis of the piston, and the piston to move in correspondence to the rocking beam along a stroke.

A pump, comprising:

• a body having a chamber in liquid communication with an inlet and an outlet, the chamber having a piston and a drive assembly to drive the piston positioned therein;
• the piston with a conduit for conducting a liquid from the chamber to the outlet;
• the drive assembly including:
• a rotatable drive shaft with an eccentric cam positioned thereon;
• a cam rod connected at one end to the eccentric cam insert, and having a slot therein;
• a rocking beam having an actuator end connected to a cross rod that serves as a pivot point, a mid portion having a slotted portion therein for connecting to the cam rod, and an output end coupled to the piston;
• and
• a pin positioned in the cam rod slot that serves to connect the rocking beam to the cam rod;
• wherein when the drive shaft is rotated, the cam rod moves in a direction parallel to a longitudinal axis of the piston, causing the rocking beam to pivot about the pivot point, the output end of the rocking beam to move in a transverse and parallel direction with respect to the longitudinal axis of the piston, and the piston to move axially.